`timescale 1ns / 1ns  // unit/precision

module led_tb ();

  reg  key_in;
  wire led_out;

  initial begin
    key_in <= 1'b1;  // release
    #200 key_in <= 1'b0;  // press
    #500 key_in <= 1'b1;  // release
    #1000 key_in <= 1'b0;  // press
    #1000 key_in <= 1'b1;  // release
  end

  led u_led (
    .key(key_in),
    .led(led_out)
  );

endmodule
